[Cobra 29]

I have used both the Crane and the Accel vacuum advance modules on an MSD disribution (GM style). The Crane advance was adjustable only with a step plate that phyiscally blocks the movement of the diafram attachment rod to the distributor plate. Because I was using a MSD versus GM distribtor I could not easily use the step plate. The Accel unit uses a allen key in the vacuum port to change BOTH the rate of advance and the LIMIT. You want to be able to change the LIMIT of advance from the module.

Presently, I am running only 5 degrees of vacuum advance for better trottle response and fuel mileage. The 5 degree limit ensures that I will not have too much total advance at any RPM given my initial and centrifical settings.